Development of a High-sensitive Refractive Index and Temperature Nano-sensor

Abstract

High perform lab-on-chip sensors packaged in a miniaturized form are replacing the bulky sensors in the point-of-care detection and allowing rapid triage, treatment, or discharge of patients. To satisfy the requirements of label-free detection, low cost, fast response of a lab-on-chip biosensor, a nanodot enhanced metal-insulator-metal (MIM) waveguide based refractive index sensor coupled with three rectangular cavities, is proposed in this work. Numerical investigation of the transmission spectra, employing the finite element method (FEM), exhibits a linear correspondence with the refractive index, which is used to sense the unknown materials. With the initial structural setup, the proposed sensor demonstrates a maximum sensitivity and FOM as 5016 nmRIU����1 and 144, respectively. Imposing a sequential optimization of the structural parameters and enhancing light-matter interaction by loading nanodots at the high E-field confined areas, desired sensitivity (S) and figure of merit (FOM) are upgraded to 7564 nmRIU����1 and 120, respectively. The proposed sensor’s temperature sensing capability is explored by filling the sensing media with alcohol and polydimethylsiloxane (PDMS). Maximum temperature sensitivity of 2:68 nm0C����1 operating from ����1000C to 600C is recorded, while for polydimethylsiloxane, the maximum temperature sensitivity of 3:40 nm0C����1 for 200C to 700C operating range is recorded. Furthermore, this work addresses some recent plasmonic sensors’ shortcomings in the selective detection of a single element from a complex solution (e.g., blood sample) and proposed a sample preparation model combining purification, molecular separation, and concentration enhancement prior to the selective detection of Na+, K+, and glucose concentration in the human blood. A refractive index model for this purpose, is developed that exposes a maximum shift of 0:83 nm, 1:23 nm, and 8:72 nm of the transmittance peak for the concentration variation of 1 mgdL����1 in Na+, K+, and glucose solution easily differentiable by the modern spectrometer. With such excellent performance metrics, compact size, and simple to use feature, the proposed sensor is expected to bring a notable solution in the point-of-care detection.